This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A076207 #11 Dec 15 2017 17:36:06 %S A076207 3,21,105,325,7875,9568125 %N A076207 Triangular numbers whose sum of primes from smallest to largest prime factor is triangular and whose sum of composites from smallest to largest prime factor is triangular. %C A076207 No more terms < 2.77*10^12. - _David Wasserman_, Jul 20 2005 %C A076207 a(7) > 2*10^15. - _Donovan Johnson_, Feb 03 2013 %e A076207 325 = 5^2*13, sum of primes between: 5+7+11+13 = 36, triangular; sum of composites between: 6+8+9+10+12 = 45, triangular. %Y A076207 Cf. A000217, A074036, A074037. %K A076207 more,nonn %O A076207 1,1 %A A076207 _Jason Earls_, Nov 02 2002 %E A076207 Offset corrected by _Donovan Johnson_, Feb 03 2013